Impact of spontaneous anterograde flow of the infarct artery on left ventricular function in patients with a first anterior wall acute myocardial infarction

To assess the impact of spontaneous anterograde flow of the infarct artery on outcomes in patients with acute myocardial infarction (AMI), we studied 478 patients with a first anterior wall AMI who underwent coronary angiography within 12 hours after the onset of chest pain; Thrombolysis In Myocardial Infarction (TIMI) 3 flow was obtained after reperfusion therapy. Patients were divided into 3 groups: 119 patients with spontaneous anterograde flow (initial TIMI 2 or 3 flow) of the infarct artery, 118 patients with an initially occluded artery (TIMI 0 or 1 flow) and time to angiography or=55% (odds ratio 7.13, 95% confidence interval 3.10 to 16.4, p <0.001). In conclusion, although very early reperfusion improved LV function more than late reperfusion, spontaneous anterograde flow was associated with better acute and predischarge LV function after AMI compared with very early reperfusion of an initially occluded artery.     

Early identification of impaired myocardial reperfusion with serial assessment of ST segments after percutaneous transluminal coronary angioplasty during acute myocardial infarction.

To evaluate the relation between ST-segment analysis and microvascular reperfusion in patients with acute myocardial infarction (AMI), we studied 51 patients with first AMI who were successfully treated by percutaneous transluminal coronary angioplasty (PTCA). The lead showing the greatest ST-segment elevation on the 12-lead electrocardiogram (ECG) was serially investigated until 24 hours after PTCA. Successful reperfusion was determined by technetium-99m tetrofosmin single-photon emission computed tomography. Impaired reperfusion (group 1: < 4 change in the sum of the defect score from before to immediately after PTCA) was observed in 24 patients, and successful reperfusion (group 2) was observed in 27 patients. Although ST-segment elevation was reduced significantly at 30 minutes after PTCA in group 2 (2.2 +/- 1.4 to 1.7 +/- 1.3 mm, p = 0.01), there was no significant change in group 1 (1.9 +/- 1.9 to 2.4 +/- 1.7 mm). Ten of 14 patients (71%) with persistent ST-segment elevation (DeltaST > 0 mm change in ST segment from before to 30 minutes after PTCA > 0) were in group 1, whereas 23 of 37 patients (62%) with ST-segment resolution (DeltaST < or = 0) were in group 2. The sensitivity and specificity of persistent ST-segment elevation for predicting impaired microvascular reperfusion were 42% and 85%, respectively. Thus, persistent ST-segment elevation 30 minutes after primary PTCA was a highly specific electrocardiographic marker of impaired reperfusion in patients with AMI.     

Impact of prodromal angina pectoris and white blood cell count on outcome of patients with acute myocardial infarction

BACKGROUND: Elevation of white blood cell (WBC) count at admission is associated with adverse outcome after acute myocardial infarction (AMI). Prodromal angina, by the mechanism of ischemic preconditioning, improves left ventricular (LV) function and survival after reperfusion therapy in patients with AMI. Recent experimental studies have reported that preconditioning has anti-inflammatory effect. METHODS: This study consisted of 598 patients with first anterior wall AMI who underwent coronary angiography within 12 h after symptom onset. WBC count was measured at the time of hospital admission. Prodromal angina was defined as angina occurring within 24 h before the onset of AMI. Serial measurements of LV ejection fraction (EF) were obtained before reperfusion therapy and before discharge in 421 patients (71%). RESULTS: High WBC count (>10.2 x 103/mm3, n=297) was associated with higher 30-day mortality (8% vs. 4%, p=0.02) and lower predischarge LVEF (51+/-15% vs. 57+/-14%, p<0.001), although there was no significant difference in acute LVEF (47+/-10% vs. 49+/-11%, p=0.07). High WBC count was an independent predictor of 30-day mortality (p=0.009) and predischarge LVEF (p=0.002). Prodromal angina was associated with lower 30-day mortality (3% vs. 7%, p=0.02) and preserved predischarge LVEF (57+/-15% vs. 53+/-14%, p=0.006). Patients with prodromal angina had lower WBC count (10.0+/-3.3 x 10(3)/mm3 vs. 11.0+/-3.9 x 10(3)/mm3, p=0.001) and prodromal angina was an independent predictor of WBC count (p<0.001). CONCLUSIONS: Elevation of WBC count and lack of prodromal angina were associated with impaired LV function and mortality after reperfusion in patients with AMI. Prodromal angina might have contributed to favorable outcome after AMI through its anti-inflammatory effect.     

Consideration of the total ST-segment deviation on the initial electrocardiogram for predicting final acute posterior myocardial infarct size in patients with maximum ST-segment deviation as depression in leads V1 through V3. A FRISC II substudy

BACKGROUND: Because patients with acute left circumflex occlusion are typically characterized primarily on the standard 12-lead electrocardiogram (ECG) by ST depression, they do not qualify to receive reperfusion therapy. Documentation of a relationship between the quantities of acute ST change and final QRS estimated acute myocardial infarction (AMI) size could form the basis for clinical trials to determine the value of reperfusion therapy. METHOD: The Fragmin and Fast Revascularization during Instability in Coronary artery disease trial included 3214 patients with unstable coronary artery disease. Two percent of the patients (n = 69) had maximum ST-segment depression in leads V 1 through V 3 and were selected for this study. Initial ECG changes were compared to final myocardial infarction size, using the Selvester QRS score as the end point. RESULTS: The quantity of initial ST-segment deviation correlated with the final AMI size (r = 0.43, P < .0005). The formula 3[0.22 (SigmaST downward arrow + SigmaST upward arrow) -0.02], where downward arrow indicates depression and upward arrow elevation, derived from measurements on the initial ECG, predicted the size of the AMI in percentage of the left ventricle as estimated on the final ECG. The study population had a large proportion of AMI (73%) indicated to be in or adjacent to the posterior left ventricular wall. CONCLUSION: The quantitative initial ST-segment deviation correlates linearly to the final AMI size in patients with maximum ST-segment depression in leads V 1 through V 3. The formula derived could be valuable for selecting patients who fail to meet strict ST-elevation AMI criteria for emergency intravenous or intracoronary reperfusion therapy.     

ST-segment depression in lead aVR predicts predischarge left ventricular dysfunction in patients with reperfused anterior acute myocardial infarction with anterolateral ST-segment elevation.

BACKGROUND: Patients with an anterolateral acute myocardial infarction (AMI) have a worse prognosis, and those with additional inferolateral wall involvement might be higher risk because of more extensive area at risk. Lead -aVR obtained by inversion of images in lead aVR has been reported to provide useful information for inferolateral lesion. METHODS: We examined the relation between ST-segment deviation in lead aVR on admission electrocardiogram (ECG) and left ventricular function in 105 patients with an anterolateral AMI undergoing successful reperfusion < or = 6 hours after onset. Patients were classified according to ST-segment deviation in lead aVR on admission ECG: group A, 23 patients with ST elevation of > or = 0.5 mm; group B, 47 patients without ST deviation; and group C, 35 patients with ST depression of > or = 0.5 mm. RESULTS: There were no differences among the 3 groups in age, sex, or site of the culprit lesion. In groups A, B, and C, the peak creatine kinase level was 3661 +/- 1428, 4440 +/- 1889, and 6959 +/- 2712 mU/mL, and the left ventricular ejection fraction (LVEF) measured by predischarge left ventriculography was 54% +/- 9%, 48% +/- 7%, and 37% +/- 9%, respectively(P < .01). During hospitalization, congestive heart failure occurred more frequently in group C than in groups A or B (P < .05). ST-segment depression in lead aVR had a higher predictive accuracy than other ECG findings in identifying patients with predischarge LVEF < or = 35%. CONCLUSIONS: We conclude that in patients with an anterolateral AMI, ST-segment depression in lead aVR on admission ECG is useful for predicting larger infarct and left ventricular dysfunction despite successful reperfusion.     

ST-segment re-elevation unrelated to left ventricular ejection fraction or volume after anterior wall acute myocardial infarction treated with successful reperfusion

Ventricular remodeling is a major determinant of the long-term prognosis of patients with acute myocardial infarction (AMI). No previous study examined the relation of ST-segment re-elevation to left ventricular (LV) volume and function in patients with successful reperfusion. We examined the relation of ST-segment re-elevation to LV function and volume indices in 51 patients with anterior wall AMI who underwent successful reperfusion by direct coronary angioplasty. A 12-lead electrocardiogram was recorded once a day until 7 days after the onset of AMI. ST-segment shift was measured and Sigma ST was defined as the sum of ST-segment elevation obtained from leads V2, V3, and V4. ST-segment re-elevation was defined as present when the difference between maximal and minimal Sigma ST (Delta ST) was >0.3mV. LV indices were obtained from left ventriculography performed approximately 1 month after the onset of AMI. ST-segment re-elevation was observed in 15 patients (29%). No significant differences were observed between the ST- re-elevation group and non-ST-re-elevation group in LV ejection fraction (49.4+/-14.0 vs. 51.2+/-11.5%), LV end-systolic volume index (35.8+/-13.1 vs. 33.8+/-12.5 mL/m(2)) or LV end-diastolic volume index (69.7+/-12.8 vs. 68.3+/-14.4 mL/m(2)). The difference between maximal and minimal Sigma ST (Delta ST) was not significantly correlated with any LV index examined. In conclusion, the present study revealed that ST-segment re-elevation after successful reperfusion in anterior wall AMI patients was not related to LV volume or function, indicating that ST-re-elevation is not a clinically meaningful indicator of LV remodeling.     

Exercise training without ventricular remodeling in patients with moderate to severe left ventricular dysfunction early after acute myocardial infarction

BACKGROUND: The purpose of this study was to determine whether or not patients with moderate to severe left ventricular (LV) dysfunction benefit from exercise training starting early after acute myocardial infarction (AMI) without deteriorating LV remodeling. METHODS: We investigated changes in exercise capacity and LV end-diastolic dimension (LVDd by two-dimensional echocardiography) before and after exercise training in 126 patients after AMI. Patients were divided into three groups according to LV ejection fraction (EF) at the beginning of exercise training: 74 patients with LVEF>/=45% (Group H), 35 patients with 35%相似文献   

Clinical implications of serial changes in ST-segment elevation after reperfusion in patients with anterior acute myocardial infarction.

BACKGROUND: In patients with acute myocardial infarction (AMI), the relationship of serial changes in ST-segment elevation after reperfusion to left ventricular (LV) function remains unclear. METHODS AND RESULTS: The study group comprised 164 patients with reperfused anterior AMI within 6 h of symptom onset. The sum of ST-segment deviation was calculated on admission (SigmaST-admission), and 1 h (SigmaST-1 h) and 24 h (SigmaST-24 h) after reperfusion. ST resolution was defined as a reduction in SigmaST-1 h of > or =50% as compared with SigmaST-admission. Patients were classified into 3 groups: group A, 82 patients with ST resolution in whom SigmaST-1 h > or = SigmaST-24 h; group B, 37 patients with ST resolution in whom SigmaST-1 h < SigmaST-24 h; group C, 45 patients without ST resolution. Peak creatine kinase were higher in groups B and C than in group A (4,578+/-2,176, 4,236+/-2,638, 2,222+/-1,926 mU/ml, p<0.01). At 6 months follow-up, the LV ejection fraction were lower in groups B and C than in group A (53+/-8, 54+/-12, 62+/-9%, p<0.01). CONCLUSIONS: An increase in ST-segment elevation 1-24 h after reperfusion, despite ST resolution, is associated with a larger infarction and poorer LV function in patients with reperfused anterior AMI.     

Reliability of resolution of ST-segment elevation after coronary reperfusion in predicting myocardial salvage in anterior wall acute myocardial infarction

Resolution of ST-segment elevation (ST resolution) after reperfusion therapy has been shown to correlate with improved left ventricular (LV) function in patients with acute myocardial infarction (AMI). However, not all patients with ST resolution have preserved LV function. We evaluated the clinical significance of ST resolution in 129 patients with anterior wall AMI who underwent successful coronary recanalization within 6 hours after symptom onset by studying the relation to myocardial blush grade, another angiographic marker of myocardial reperfusion. A reduction of > or =50% in ST-segment elevation after recanalization was defined as ST resolution. Ninety-eight patients had ST resolution and 31 patients did not. Patients with ST resolution were subdivided into 2 groups according to myocardial blush grade after recanalization: 67 patients with blush grade 2 or 3, and 31 with blush grade 0 or 1. The QRS score after recanalization was higher (5.9 +/- 1.9 vs 3.4 +/- 2.0, p <0.01) and predischarge LV ejection fraction was lower (39 +/- 8% vs 57 +/- 9%, p <0.01) in patients with blush grade 0 or 1 than in those with blush grade 2 or 3. However, the QRS score after recanalization and the predischarge LV ejection fraction were similar in patients who had ST resolution with blush grade 0 or 1 and in those without ST resolution. Our findings suggest that ST resolution after recanalization does not consistently predict myocardial salvage in patients with anterior AMI.     

Significance of neutrophil counts after reperfusion therapy in patients with a first anterior wall acute myocardial infarction.

BACKGROUND: Previous studies have demonstrated that an elevated neutrophil count on admission is associated with a higher risk of adverse events after acute myocardial infarction (AMI). However, the significance of the neutrophil count after reperfusion therapy has not been elucidated. METHODS AND RESULTS: The association of the neutrophil count on admission and days 2 and 3 with peak creatine kinase (CK) concentration, ST-segment resolution (a marker of myocardial tissue-level reperfusion), and left ventricular (LV) function at predischarge were examined in 122 patients (102 men, 20 women, mean age 61+/-11 years) with a first anterior wall AMI. Neutrophil counts were increased on day 2 and decreased on day 3 compared with admission (8,768+/-3,005 mm3, 6,617+/-2,424 mm3, and 7,725+/-3,388 mm3, respectively). Patients with ST-segment resolution (n=52) had lower neutrophil counts on days 2 and 3 than those without it (n=70), but neutrophil counts on admission did not differ significantly between patients with and without ST-segment resolution. Neutrophil counts on admission and days 2 and 3 were weakly but significantly correlated with peak CK concentration (r=0.31, p=0.0004; r=0.43, p<0.0001; r=0.32, p=0.003, respectively) and with LV ejection fraction at predischarge (r=-0.18, p=0.04; r=-0.26, p=0.003; r=-0.27, p=0.003; respectively). CONCLUSION: The neutrophil count after reperfusion is weakly but significantly correlated with infarct size, myocardial tissue-level reperfusion, and LV function at predischarge in a first anterior wall AMI. These correlations were slightly stronger than the correlations with the neutrophil count on admission.     

Influence of baseline ejection fraction and success of thrombolysis on mortality and ventricular function after acute myocardial infarction

The efficacy of streptokinase (STK) thrombolytic therapy was prospectively evaluated in 77 consecutive patients presenting within 9 hours of onset of acute myocardial infarction. Serial left ventricular (LV) ejection fraction (EF) was assessed by radionuclide ventriculography, initially (acute) and at 1 month (late). The role of initial LVEF was examined by comparing patients with an acute LVEF greater than or equal to 50% (type I) with those with LVEF less than 50% (type II). Sixty-five patients (84%) had total coronary occlusion and received STK. Initial successful reperfusion was achieved in 34 patients (52%), but repeat angiograms at 10 to 14 days revealed persistent patency in only 27 patients. Within the type I and type II classification, 2 patient subgroups were compared: Group A had successful and persistent thrombolysis and group B had initial failure of thrombolysis or in-hospital reocclusion. There was no significant change in global LVEF in any group from acute to 1 month follow-up: group IA--acute EF = 56 +/- 2% (mean +/- standard error of the mean), late EF = 55 +/- 2% (p = not significant [NS]); group IB--acute EF = 58 +/- 1%, late EF = 55 +/- 2% (NS); group IIA--acute EF = 35 +/- 2%, late EF = 4 +/- 4%, (NS); group II B--acute EF = 36 +/- 2%, late EF = 41 +/- 3% (NS). No patient with an acute EF greater than or equal to 50% died, i.e., group IA patients (n = 7) or group IB patients (n = 13).(ABSTRACT TRUNCATED AT 250 WORDS)     

Diagnosis of acute myocardial infarction in angiographically documented occluded infarct vessel : limitations of ST-segment elevation in standard and extended ECG leads.

STUDY OBJECTIVES: The majority of thrombolysis studies require defined ST-segment elevations as an inclusion criterion for the diagnosis of acute myocardial infarction (AMI). However, depending on the occluded infarct vessel and the criteria applied, the ECG diagnosis of AMI can be difficult to establish. Accordingly, this study was performed to evaluate the sensitivity of ST-segment elevation of standard and extended ECG leads in a cohort of patients with angiographically confirmed diagnosis of AMI. PATIENTS AND METHODS: In 418 patients (mean +/- SD age, 60 +/- 13 years) with AMI (pain onset, 4.8 +/- 3.0 h), coronary angiography with percutaneous transluminal coronary angioplasty/stenting of the culprit lesion was performed. The diagnosis of AMI was confirmed by emergency coronary angiography and laboratory analyses. ST-segment elevation (in two contiguous leads) of 1 mm in standard lead I through aVF and ST-segment elevations of 2 mm (or 1 mm, corresponding values presented in parentheses) in V(1) through V(6) were considered significant. In a subset of 102 AMI patients, additional right precordial leads V(3)R through V(6)R for evaluation of right ventricular infarction and additional chest leads V(7) through V(9) for evaluation of posterior infarction were recorded. ST-segment elevations of 1 mm in the right precordial leads and 1 mm or 0.5 mm in the posterior leads were considered significant. RESULTS: Standard leads I through V(6) showed ST-segment elevation in 85% (96%) of patients with left anterior descending artery occlusion, in 46% (61%) of patients with left circumflex coronary artery (CX) occlusion, and in 85% (90%) of patients with right coronary artery occlusion. On consideration of additional ECG tracings in the subgroup of 102 patients (V(3)R through V(6)R and V(7) through V(9)), the respective numbers increased by 2 to 8% depending on different criteria for ST-segment elevation; in patients with CX occlusion, the increase amounted to 6 to 14%. There was a trend toward an extended infarct size (maximum creatine kinase [CK] values) with concomitant ST-segment elevation in additional ECG leads as assessed by maximum CK levels. CONCLUSIONS: The sensitivity of the ECG diagnosis of AMI is only marginally increased by extended precordial chest leads. There is a trend toward an extended infarct size in those patients with concomitant ST-segment elevation in additional ECG leads.     

Prediction of remote left ventricular volumes and functions after acute myocardial infarction with successful coronary intervention.

BACKGROUND: The scintigraphic perfusion defect size (DS) at 1 week after acute myocardial infarction (AMI) predicts remote left ventricular (LV) volumes and LV ejection fraction (LVEF). The present study examined whether LV volumes and LVEF 6 months after AMI may be better predicted by the combination of LV volumes and LVEF just after reperfusion, and DS at 1 week, after AMI in patients with Thrombolysis In Myocardial Infarction (TIMI) grade III reperfusion by percutaneous coronary intervention. METHODS AND RESULTS: In 48 patients with AMI and TIMI grade III reperfusion, quantitative gated SPECT (QGS) was performed just after reperfusion, and at 1 week and 6 months after AMI. LV end-diastolic volume index decreased (108+/-8 to 93+/-6 ml/m(2), p<0.05) and LVEF increased (44+/-3 to 50+/-2%, p<0.05) 6 months after AMI. In addition, they were better predicted by a combination of LV volumes and LVEF just after reperfusion and DS at 1 week after AMI. CONCLUSIONS: In AMI with TIMI grade III reperfusion, LV volumes and LVEF at 6 months after MI correlate with the values obtained just after reperfusion. Myocardial perfusion imaging combined with QGS at reperfusion may predict these late-phase parameters.     

Effects of reperfusion on left ventricular ejection fraction and volume after acute myocardial infarction.

The effects of reperfusion on left ventricular (LV) function and volume were studied in patients with evolving acute myocardial infarction (AMI). We analyzed the LV ejection fraction and volume in patients who had been admitted within 24 h of the onset of their first AMI with culprit lesion of #6, #7 and #1 (American Heart Association classification). Sixty-five patients (Re group) received successful reperfusion therapy within 6 h after the AMI. The other 60 patients (Oc group), who were admitted from 6 to 24 h after the AMI, received conservative therapy. Patients with re-obstruction of the culprit lesion after reperfusion therapy were excluded from the Re group. Patients with spontaneous recanalization following conservative therapy were excluded from the Oc group. The LV ejection fraction (LVEF), LV end-systolic volume index (LVESVI), and LV end-diastolic volume index (LVEDVI) were measured using a modified Dodge's formula by left ventriculography performed 4 weeks after the AMI. LVEF in the Re group was significantly greater than in the Oc group (57 +/- 12 vs 49 +/- 11%) (mean +/- SD, p less than 0.01). LVESVI in the Re group was significantly smaller than in the Oc group (30 +/- 13 vs 38 +/- 16 ml/m2, p less than 0.01). Although LVEDVI was not significantly different between the 2 groups, in patients with a responsible coronary lesion of segment #6, LVEDVI in the Re group was significantly smaller than in the Oc group (67 +/- 14 vs 77 +/- 18 ml/m2, p less than 0.05). Although LVEF and LV volume correlated in both groups, the correlation was weak (r = 0.40-0.42), suggesting that LV volume was not dependent solely on LV functional recovery. The incidence of ventricular aneurysm in the Re group was significantly lower than in the Oc group (15.4 vs 45.0%, p less than 0.01). Multivariate analysis selected reperfusion of the responsible coronary artery as one of the factors significantly associated with a reduction of LVEDVI, LVESVI, an improvement of LVEF, and a decrease in the rate of aneurysm formation. In summary, our results indicated that reperfusion improved EF, reduced LV volume, and decreased the rate of aneurysm formation as compared to non-reperfusion, which suggests that reperfusion therapy is beneficial for both functional recovery and ventricular remodeling.     

Factors that determine the direction and magnitude of precordial ST-segment deviations during inferior wall acute myocardial infarction

Sixty-one patients with inferior acute myocardial infarction (AMI) and no evidence of prior AMI were studied to determine which factors influence the magnitude of precordial ST-segment depression. In the total study group, there was a significant but weak correlation between the magnitude of precordial ST-segment depression and the magnitude of inferior ST-segment elevation (r = -0.46, p less than 0.001). In the 29 patients with evidence of concomitant right ventricular (RV) involvement, precordial ST-segment depression was significantly smaller both in absolute terms (-1.3 +/- 1.8 vs -2.8 +/- 1.9 mm, p less than 0.01) and relative to the magnitude of inferior ST-segment elevation (ratio of -0.2 +/- 1.0 vs -1.1 +/- 0.5, p less than 0.01), whereas in the 15 patients with lateral ST-segment elevation (greater than or equal to 1 mm in lead V6), precordial ST-segment depression was significantly greater both in absolute terms (-3.5 +/- 2.3 vs -1.6 +/- 1.7 mm, p less than 0.01) and relative to the magnitude of inferior ST-segment elevation (ratio of -1.1 +/- 0.8 vs -0.5 +/- 0.9, p less than 0.02). Consistent with these findings, the correlation between the magnitudes of precordial and inferior ST-segment deviations was considerably improved when only the 24 patients with neither evidence of RV involvement nor lateral ST-segment elevation were analyzed (r = 0.89, p less than 0.001, n = 24). These data suggest that in patients with inferior AMI, there is a reciprocal relation between precordial and inferior ST-segment deviations, which is distorted by concomitant RV involvement and by concomitant lateral left ventricular wall involvement.     

Persistent ST-segment elevation after primary stenting for acute myocardial infarction: its relation to left ventricular recovery

BACKGROUND: Early restoration of coronary artery patency in acute myocardial infarction (AMI) has been linked to improvement in survival. However, early recanalization of an occluded epicardial coronary artery by either thrombolytic agents or percutaneous transluminal coronary angioplasty (PTCA) does not necessarily lead to left ventricular (LV) function recovery. HYPOTHESIS: The aim of this study was to evaluate the relation between persistent ST elevation shortly after primary stenting for acute myocardial infarction (AMI) and LV recovery. METHODS: Thirty-one patients with primary stenting for AMI were prospectively enrolled. To evaluate the extent of microvascular injury, serial ST-segment analysis on a 12-lead electrocardiogram recording just before and at the end of the coronary intervention was performed. Persistent ST-segment elevation (Persistent Group, n = 11) was defined as > or = 50% of peak ST elevation and resolution (Resolution Group, n = 20) was defined as < 50% of peak ST elevation. Echocardiography was performed on Day 1 and 3 months after primary stenting. RESULTS: At 3 months, infarct zone wall-motion score index (WMSI, 2.1 +/- 0.6 vs. 2.7 +/- 0.3, p < 0.05) was smaller in the Resolution Group than in the Persistent Group, whereas wall motion recovery index (RI, 0.4 +/- 0.3 vs. 0.1 +/- 0.2, p < 0.05) and ejection fraction (58 +/- 5 vs. 43 +/- 10%, p < 0.05) were larger in the Resolution Group than in the Persistent Group. The extent of persistent ST elevation (% ST) shortly after successful recanalization of the infarct-related artery was significantly related to RI at 3 months (r = -0.4, p < 0.05). However, time to reperfusion was not related to RI at 3 months. There was also significant correlation between corrected TIMI frame count and %ST (r = 0.4, p < 0.05). CONCLUSIONS: Persistent ST-segment elevation shortly after successful recanalization (> or = 50% of the peak value), as a marker of impaired microvascular reperfusion, predicts poor LV recovery 3 months after primary stenting for AMI.     

Predischarge low-dose dobutamine test and prediction of left ventricular function at 1 year in patients with a first anterior myocardial infarction

BACKGROUND: It is unclear whether spontaneous improvement in contractility following acute myocardial infarction (AMI) is related to severity of predischarge systolic dysfunction and can be predicted by isotopic ventriculography with a low-dose dobutamine test (DBT). HYPOTHESIS: Spontaneous improvement in contractility would be similar in patients with more preserved and those with depressed ventricular function, and a DBT test could predict it. METHODS: Left ventricular ejection fraction (LVEF), regional contractility score (RCS), and left ventricular end-diastolic volume index (EDVI) at predischarge, during DBT, and at 1 year were analyzed in 43 patients with a first anterior ST-elevation AMI. RESULTS: Changes produced by DBT in patients with LVEF < 40%, RCS > or = 3, or EDVI > or = 70 ml/m2 were smaller than in those observed at 1 year (LVEF: 30 +/- 5-35 +/- 7%, p < 0.001, vs. 39 +/- 10%, p = 0.005; RCS: 4.9 +/- 1.4-4.6 +/- 2.0, NS, vs. 3.4 +/- 2.0, p < 0.02; EDVI: 92 +/- 14-86 +/- 22, NS, vs. 78 +/- 23 ml/m2, p < 0.03). In contrast, in patients with EF > or = 40%, RCS < 3 or EDVI < 70 ml/m2, changes with DBT tended to be greater than those observed at 1 year (LVEF: 52 +/- 8-57 +/- 11%, p < 0.004 vs. 55 +/- 11%, p < 0.04); RCS: 1.1 +/- 0.9-0.8 +/- 0.8, NS, vs. 1.1 +/- 1.1, NS; and EDVI: 51 +/- 9-47 +/- 11, p < 0.005, vs. 54 +/- 13 ml/m2, NS). CONCLUSIONS: Among patients with a first anterior AMI, spontaneous improvement in contractility at 1 year was greatest in those with a more depressed ventricular function or a dilated ventricle, but its magnitude was underestimated by a predischarge DBT test.     

Markers of myocardial reperfusion as predictors of left ventricular function recovery in acute myocardial infarction treated with primary angioplasty

BACKGROUND: Myocardial blush grade (MBG), corrected TIMI frame count (cTFC), and ST-segment reduction are indices of myocardial reperfusion. HYPOTHESIS: We evaluated their predictive value for left ventricular (LV) function recovery by gated single-photon emission computed tomography (SPECT) after acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (PCI). METHODS: In 40 patients with AMI, gated SPECT was performed at admission and repeated 7 and 30 days after PCI. Left ventricular function recovery was defined as an increase > or = 10 points in SPECT LV ejection fraction from baseline to 1 month. The MBG, cTFC, and ST-segment elevation index 1 h after PCI were determined to evaluate reperfusion. RESULTS: Twenty-four patients (Group 1) had LV function recovery and 16 (Group 2) did not. A significant correlation was found between LV function recovery and MBG (r = 0.66; p = 0.0001), and ST-segment elevation index at 1 h (r = -0.55; p = 0.0001), but not with cTFC. Univariate predictors of LV function recovery were MBG (p = 0.0003) and ST-segment elevation index 1 h after intervention (p = 0.0026), but not cTFC. In a multivariate analysis, MBG was the only predictor of LV function recovery. Myocardial blush grade > or = 2 and ST-segment elevation index reduction had the same accuracy (88%) for predicting LV function recovery. Lower accuracy (75%) was shown by fast cTFC (< 23 frames). Myocardial blush grade > or = 2 showed the better negative likelihood ratio, and ST-segment elevation index reduction had the higher positive likelihood ratio in predicting LV function recovery. CONCLUSIONS: Myocardial blush grade was the best parameter for prediction of LV function recovery: MBG > or = 2 and ST-segment elevation index reduction showed good accuracy in predicting LV function recovery. The cTFC failed to be a significant predictor.     

Nicorandil, a potent cardioprotective agent, reduces QT dispersion during coronary angioplasty

BACKGROUND: Previous studies have found that ST-segment elevation and QT dispersion are smaller in second coronary occlusions than in first occlusions, a trend that suggests ischemic preconditioning. It has not been established whether nicorandil reduces ST-segment elevation and QT dispersion during coronary angioplasty. METHODS AND RESULTS: Thirty patients with stable angina undergoing coronary angioplasty in the proximal left anterior descending artery were randomly assigned to one of two groups, receiving either 5 mg oral nicorandil 3 times daily (n = 15) or placebo (n = 15). In the control patients, the total ST-segment elevation decreased from 14 +/- 3 mm during the first inflation to 7 +/- 2 mm during the second inflation (P < .01). In contrast, in the nicorandil-treated patients, the total ST-segment elevation during the second inflation was roughly equivalent to that during the first inflation (8 +/- 3 mm vs 8 +/- 3 mm, P = not significant). After the first reperfusion, a significantly smaller increase in QT dispersion was observed in the nicorandil-treated patients than in the control patients (43 +/- 15 ms vs 54 +/- 15 ms, P < .001). However, after the second reperfusion, QT dispersion was similar for the two groups (32 +/- 15 ms vs 34 +/- 13 ms, P = not significant). CONCLUSIONS: Nicorandil may precondition the myocardium and may prevent the occurrence of ventricular arrhythmias after coronary reperfusion by suppressing the increase in QT dispersion.     

Diabetes mellitus is associated with insufficient microvascular reperfusion following revascularization for anterior acute myocardial infarction

OBJECTIVE: The purpose of this study was to test the hypothesis that lack of microvascular reperfusion following revascularization might be associated with a poor clinical outcome in diabetic patients with acute myocardial infarction (AMI). METHODS: We studied 134 patients with a first anterior AMI who underwent successful revascularization within 6 hours. We assessed microvascular reperfusion by using electrocardiogram recordings just before revascularization and on return to the coronary care unit. Lack of microvascular reperfusion was defined as the absence of decrease of > or = 20% in the sum of ST segment elevation (sigmaST). RESULTS: Twenty-four patients had diabetes and 110 patients did not. SigmaST before revascularization was similar between diabetic and nondiabetic patients. After revascularization, reduction of sigmaST was significantly smaller (1.3 +/- 8.4 mm vs 6.5 +/- 10.8 mm, p = 0.03), and lack of microvascular reperfusion was significantly more frequent (62.5% vs 33.6%, p = 0.01) in diabetic patients. A multivariate analysis showed that diabetes was associated with insufficient microvascular reperfusion (odds ratio 3.18, p = 0.03). Major adverse cardiac events occurred more frequently in patients with a lack of microvascular reperfusion (30.8% vs 15.9%, p = 0.04). CONCLUSION: These findings suggest that lack of microvascular reperfusion following revascularization may be one of the mechanisms of a poor clinical outcome in diabetic patients with AMI.